sublet: help requested

[adorno3a]

I am subletting my rent stabilized apartment and have a few questions. I have proceeded according to the steps listed on this website. The landlord then requested that I fill out an application asking for additional information. According to this site he is allowed to do this as long as it is not "unduly burdonsome". Is asking about my finances (when I have always paid my rent on time) qualify? And what about charging me $50 in an "application fee"? My main question is what constitues the "reasonable grounds" that might allow him to reject the sublet? Can the fact that the subletter has already moved in be used against me? Thanks in advance for any help.
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